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Title: Orbital-occupancy versus charge ordering and the strength of electron correlations in electron-doped CaMnO 3

Abstract

The structural, electronic, and magnetic properties of mixed-valence compounds are believed to be governed by strong electron correlations. Here we report benchmark density-functional calculations in the spin-polarized generalized-gradient approximation (GGA) for the ground-state properties of doped CaMnO{sub 3}. We find excellent agreement with all available data, while inclusion of strong correlations in the GGA+U scheme impairs this agreement. We demonstrate that formal oxidation states reflect only orbital occupancies, not charge transfer, and resolve outstanding controversies about charge ordering.

Authors:
 [1];  [1];  [1];  [1];  [1];  [1]
  1. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
931685
DOE Contract Number:  
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 99; Journal Issue: 3
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CALCIUM OXIDES; MANGANESE OXIDES; ELECTRON CORRELATION; ELECTRONIC STRUCTURE; ORDER PARAMETERS; MAGNETIC PROPERTIES; DENSITY FUNCTIONAL METHOD; GROUND STATES; DOPED MATERIALS; VALENCE

Citation Formats

Luo, Weidong, Franceschetti, Alberto G, Varela del Arco, Maria, Tao, Jing, Pennycook, Stephen J, and Pantelides, Sokrates T. Orbital-occupancy versus charge ordering and the strength of electron correlations in electron-doped CaMnO3. United States: N. p., 2007. Web. doi:10.1103/PhysRevLett.99.036402.
Luo, Weidong, Franceschetti, Alberto G, Varela del Arco, Maria, Tao, Jing, Pennycook, Stephen J, & Pantelides, Sokrates T. Orbital-occupancy versus charge ordering and the strength of electron correlations in electron-doped CaMnO3. United States. doi:10.1103/PhysRevLett.99.036402.
Luo, Weidong, Franceschetti, Alberto G, Varela del Arco, Maria, Tao, Jing, Pennycook, Stephen J, and Pantelides, Sokrates T. Mon . "Orbital-occupancy versus charge ordering and the strength of electron correlations in electron-doped CaMnO3". United States. doi:10.1103/PhysRevLett.99.036402.
@article{osti_931685,
title = {Orbital-occupancy versus charge ordering and the strength of electron correlations in electron-doped CaMnO3},
author = {Luo, Weidong and Franceschetti, Alberto G and Varela del Arco, Maria and Tao, Jing and Pennycook, Stephen J and Pantelides, Sokrates T},
abstractNote = {The structural, electronic, and magnetic properties of mixed-valence compounds are believed to be governed by strong electron correlations. Here we report benchmark density-functional calculations in the spin-polarized generalized-gradient approximation (GGA) for the ground-state properties of doped CaMnO{sub 3}. We find excellent agreement with all available data, while inclusion of strong correlations in the GGA+U scheme impairs this agreement. We demonstrate that formal oxidation states reflect only orbital occupancies, not charge transfer, and resolve outstanding controversies about charge ordering.},
doi = {10.1103/PhysRevLett.99.036402},
journal = {Physical Review Letters},
number = 3,
volume = 99,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}